Serological Profile for Major Respiratory Viruses in Unvaccinated Cows from High-Yielding Dairy Herds.

This study aims to determine the serological profile of high-yielding dairy cows for four main viruses (bovine alphaherpesvirus 1 (BoAHV1), bovine viral diarrhea virus (BVDV), bovine parainfluenza virus 3 (BPIV3), and bovine respiratory syncytial virus (BRSV)) related to bovine respiratory disease (BRD) in cattle herds worldwide. In this survey, 497 blood serum samples were collected from non-vaccinated dairy cows without clinical respiratory signs in 39 herds in the central-eastern mesoregion of Paraná State, South Brazil. The presence of neutralizing antibodies was determined by virus neutralization (VN) tests. VN antibodies against BoAHV1, BVDV, BPIV3, and BRSV were detected in 355 (71.4%), 280 (56.3%), 481 (96.8%), and 315 (63.4%) serum samples, respectively. The frequencies of seropositive herds for BoAHV1, BVDV, BPIV3, and BRSV were 79.5 (n = 31), 82.0 (n = 32), 100 (n = 39), and 84.6% (n = 33), respectively. The frequencies of seropositive cows varied according to the type of herd management and the number of cows in the herd. The detection of VN antibodies in unvaccinated dairy cattle herds demonstrated the endemic circulation of the four viruses in the herds evaluated. For BRD prevention, it is recommended to implement a vaccination program for cows that provides passive immunity in calves and active immunity in cows.

The MVA vector expressing the F protein of bovine respiratory syncytial virus is immunogenic in systemic and mucosal immunization routes.

Bovine respiratory syncytial virus (BRSV) affects both beef and dairy cattle, reaching morbidity and mortality rates of 60-80% and 20%, respectively. The aim of this study was to obtain a recombinant MVA expressing the BRSV F protein (MVA-F) as a vaccine against BRSV and to evaluate the immune response induced by MVA-F after systemic immunization in homologous and heterologous vaccination (MVA-F alone or combined with a subunit vaccine), and after intranasal immunization of mice. MVA-F administered by intraperitoneal route in a homologous scheme elicited levels of neutralizing antibodies similar to those obtained with inactivated BRSV as well as better levels of IFN-γ secretion. In addition, nasal administration of MVA-F elicited local and systemic immunity with a Th1 profile. This study suggests that MVA-F is a good candidate for further evaluations combining intranasal and intramuscular routes, in order to induce local and systemic immune responses, to improve the vaccine efficacy against BRSV infection.

Serological profile of respiratory viruses in unvaccinated steers upon their arrival at Brazilian feedlot facilities.

Bovine viral diarrhea virus (BVDV), bovine alphaherpesvirus 1 (BoAHV1), bovine respiratory syncytial virus (BRSV), and bovine parainfluenza virus 3 (BPIV-3) are involved in bovine respiratory disease. These viruses can infect the respiratory system and cause considerable economic losses to beef and dairy cattle herds. This study aimed to determine the serological profiles of steers for BVDV, BoAHV1, BRSV, and BPIV-3 upon their arrival at Brazilian feedlot facilities. A total of 1,282 serum samples from unvaccinated steers were obtained on the first day of feeding. Samples were collected from 31 beef cattle herds reared in an extensive rearing system in six Brazilian states. Antibodies against BVDV, BoAHV1, BRSV, and BPIV-3 were detected using a virus neutralization test. The steers were distributed in agreement with their age and the Brazilian state of origin. The highest seropositivity was for BoAHV1 and BPIV-3 at 92.1% (1,154/1,253) and 86.6% (1,100/1,270), respectively. The seropositivity of BRSV was 77.1% (959/1,244). BVDV presented a lower rate, at slightly more than 50% (51.8%; 656/1,266). Age was a risk factor for the presence of antibodies against BVDV, BoAHV1, and BPIV-3 but not BRSV. A positive correlation was identified between BoAHV1 and BPIV-3 (P = 0.85) and between BRSV and BPIV-3 (P = 0.47). The high rate of seropositive steers for these four respiratory viruses on the first day of confinement identified in this serological survey provides important epidemiological information on respiratory infections, as the seropositivity of the four main bovine respiratory viruses in Brazilian beef cattle herds in an extensive rearing system.

Bovine respiratory syncytial virus infection in feedlot cattle cases in Argentina.

Although bovine respiratory syncytial virus (BRSV) infection has been reported in cattle in Argentina, it has not been associated with pneumonia in Argentina. We report here 5 cases of bovine pneumonia associated with BRSV. Autopsies were performed on 35 beef cattle with gross and/or microscopic lesions of pneumonia from 3 commercial feedlots. Lung samples in 5 of 35 animals were BRSV-positive by reverse-transcription nested PCR. The lungs of 2 of these 5 animals were coinfected with Mannheimia haemolytica, and 1 with bovine viral diarrhea virus 1. Microscopically, the lungs of 3 of the 5 BRSV PCR-positive animals had fibrinosuppurative bronchopneumonia, with or without pleuritis; 2 of the 5 had interstitial pneumonia. We conclude that BRSV is part of the bovine respiratory disease complex in Argentina.

Dynamics of neutralizing antibodies against Bovine respiratory syncytial virus in a dairy herd from Santa Fe Province, Argentina

Abstract Bovine respiratory syncytial virus (BRSV) is one of the most relevant agents responsi-ble for respiratory disease in cattle from both dairy and beef farms. BRSV is spread by horizontalcontact causing a constant presence of seropositive animals that favors viral circulation throughout the year. Moreover, reinfections with BRSV are frequent between animals regardless of theirage as BRSV does not confer long-lasting protective immunity. Several studies have demonstrated the circulation of BRSV in cattle from different regions of the world; however, little isknown about the dynamics of BRSV infection in cows before and after they begin lactation. Theaim of this work was to study the dynamics of BRSV neutralizing antibodies from birth up to36 months of age in a closed dairy herd of Argentina specifically around the lactation period. Passive maternal antibodies against BRSV started to decrease monthly and became almost undetectable at 8 months of age. We detected two potential infection points at months 11 and 27after birth, in which 30% and 45% of the animals showed seroconversion, respectively. Specifically, an increase in the proportion of seropositive cows after the start of lactation suggests thatthey became reinfected around the time they began lactating. We demonstrate the importanceof understanding BRSV dynamics in a closed dairy herd to review the vaccination schedule ofthe animals to achieve protection against BRSV infection.

Resumen El virus respiratorio sincitial bovino (Bovine respiratory syncytial virus, [BRSV]) es uno de los principales agentes responsables de la enfermedad respiratoria en bovinos, tanto de tambos como de cría. El virus se transmite horizontalmente y causa la presencia constante de animales seropositivos, lo cual favorece la circulación viral a lo largo del ano. A su vez, las reinfecciones por BRSV son frecuentes entre animales independientemente de su edad, dado que el virus no confiere inmunidad protectora a largo plazo. Numerosos estudios han demostrado la circulación de BRSV en bovinos de diferentes regiones del mundo, sin embargo, poco se conoce acerca de la dinámica de infección en vacas antes y después del inicio de la fase de lactancia. El objetivo de este trabajo fue estudiar la dinámica de anticuerpos neutralizantes anti- BRSV en vacas lecheras desde el nacimiento hasta los 36 meses de vida en un tambo cerrado de Argentina, específicamente, en el período de lactancia. Los anticuerpos pasivos específicos para BRSV comenzaron a declinar mensualmente hasta ser casi indetectables a los 6 meses. Detectamos dos potenciales puntos de infección a los meses 11 y 27 luego del nacimiento, momentos en los que el 30 y el 45% de los animales mostraron seroconversión, respectivamente. El incremento en la proporción de vacas seropositivas luego del comienzo de la lactancia sugiere que estas se reinfectaron en el inicio de dicha etapa. Demostramos la importancia de entender la dinámica de circulación del BRSV en un tambo cerrado, a fin de revisar el esquema de vacunación de los animales para que estén protegidos frente a la posible infección por este virus.

Dynamics of neutralizing antibodies against Bovine respiratory syncytial virus in a dairy herd from Santa Fe Province, Argentina.

Bovine respiratory syncytial virus (BRSV) is one of the most relevant agents responsible for respiratory disease in cattle from both dairy and beef farms. BRSV is spread by horizontal contact causing a constant presence of seropositive animals that favors viral circulation throughout the year. Moreover, reinfections with BRSV are frequent between animals regardless of their age as BRSV does not confer long-lasting protective immunity. Several studies have demonstrated the circulation of BRSV in cattle from different regions of the world; however, little is known about the dynamics of BRSV infection in cows before and after they begin lactation. The aim of this work was to study the dynamics of BRSV neutralizing antibodies from birth up to 36 months of age in a closed dairy herd of Argentina specifically around the lactation period. Passive maternal antibodies against BRSV started to decrease monthly and became almost undetectable at 8 months of age. We detected two potential infection points at months 11 and 27 after birth, in which 30% and 45% of the animals showed seroconversion, respectively. Specifically, an increase in the proportion of seropositive cows after the start of lactation suggests that they became reinfected around the time they began lactating. We demonstrate the importance of understanding BRSV dynamics in a closed dairy herd to review the vaccination schedule of the animals to achieve protection against BRSV infection.

El virus respiratorio sincitial bovino (Bovine respiratory syncytial virus, [BRSV]) es uno de los principales agentes responsables de la enfermedad respiratoria en bovinos, tanto de tambos como de cría. El virus se transmite horizontalmente y causa la presencia constante de animales seropositivos, lo cual favorece la circulación viral a lo largo del año. A su vez, las reinfecciones por BRSV son frecuentes entre animales independientemente de su edad, dado que el virus no confiere inmunidad protectora a largo plazo. Numerosos estudios han demostrado la circulación de BRSV en bovinos de diferentes regiones del mundo, sin embargo, poco se conoce acerca de la dinámica de infección en vacas antes y después del inicio de la fase de lactancia. El objetivo de este trabajo fue estudiar la dinámica de anticuerpos neutralizantes anti- BRSV en vacas lecheras desde el nacimiento hasta los 36 meses de vida en un tambo cerrado de Argentina, específicamente, en el período de lactancia. Los anticuerpos pasivos específicos para BRSV comenzaron a declinar mensualmente hasta ser casi indetectables a los 6 meses. Detectamos dos potenciales puntos de infección a los meses 11 y 27 luego del nacimiento, momentos en los que el 30 y el 45% de los animales mostraron seroconversión, respectivamente. El incremento en la proporción de vacas seropositivas luego del comienzo de la lactancia sugiere que estas se reinfectaron en el inicio de dicha etapa. Demostramos la importancia de entender la dinámica de circulación del BRSV en un tambo cerrado, a fin de revisar el esquema de vacunación de los animales para que estén protegidos frente a la posible infección por este virus.

Mycoplasma bovis and viral agents associated with the development of bovine respiratory disease in adult dairy cows.

The etiology and pathologic findings of bovine respiratory disease (BRD) in adult dairy cows (n = 35) from a commercial dairy herd in Southern Brazil were investigated. Pulmonary samples were examined for histopathologic patterns and specific features within these patterns, while immunohistochemical (IHC) assays were designed to detect the intralesional antigens of viral infectious disease agents and Mycoplasma bovis. Pneumonia was diagnosed in 91.4% (32/35) of these cases; neither pneumonia nor any of the infectious disease pathogens evaluated occurred in three cows. The presence of multiple respiratory pathogens in 75% (24/32) of these cases indicated the complex origin of pneumonia in cattle. Interstitial pneumonia, necrosuppurative bronchopneumonia and suppurative bronchopneumonia were the principal patterns of pulmonary disease identified by histopathology. The most frequent pathogens identified by IHC were bovine viral diarrhea virus (BVDV; n = 18), M. bovis (n = 16) and bovine alphaherpesvirus type 1 (BoHV-1; n = 14), followed by bovine respiratory syncytial virus (BRSV; n = 11) and bovine parainfluenza virus type 3 (BPIV-3; n = 5). Obliterative bronchiolitis and peribronchial lymphocytic cuffings were the characteristic histopathologic features associated with M. bovis. Necrohemorrhagic bronchitis with bronchial angiogenesis was associated with BoHV-1. Necrotizing bronchitis and bronchiolitis were associated with BVDV, BoHV-1 and BRSV. Ballooning degeneration of the bronchial and bronchiolar epithelia was associated with BRSV and BoHV-1. This is the first report from Brazil that correlated the histopathologic findings of BRD with the associated infectious disease agents by immunohistochemistry. M. bovis was frequently detected in the tissues of cows with fatal pulmonary disease during this study and may be a possible primary disease pathogen associated with the development of BRD in dairy cows. Additionally, the histopathologic features identified within patterns of pulmonary disease during this investigation may be an efficient diagnostic tool to associate histopathologic findings with specific agents of BRD in dairy cows.

Seroprevalence and risk factor associated with respiratory viral pathogens in dual-purpose cattle of Aguachica, Rio de Oro, and La Gloria municipalities in Cesar department, Colombia.

AIM: The research was conducted to determine the seroprevalence and risk factor associated with respiratory viral pathogens in dual-purpose cattle of Aguachica, Rio de Oro and La Gloria municipalities in Cesar department, Colombia. MATERIALS AND METHODS: The seroprevalence study was done from the random sampling (n=1000) of blood collected from 29 dual-purpose herds, located in three municipalities (Aguachica, Rio de Oro, and La Gloria) of Cesar department. The presence of antibodies against bovine herpesvirus type 1 (BHV-1), bovine respiratory syncytial virus (BRSV), bovine viral diarrhea virus (BVDV), and bovine parainfluenza-3 virus (BPI-3V) in the samples was detected by indirect enzyme-linked immunosorbent assay. Epidemiological data were obtained using a questionnaire administered to the owner or manager of each herd. RESULTS: The overall highest seroprevalence was observed for BHV-1 (94.7%), followed by BRSV (98.6%), BVDV (35.2%), and BPI-3V (47.1%). Regarding the seroprevalence by municipalities, there was a statistical association (p<0.05) for BVDV; however, for BRSV, BHV-1, and BPI-3V, no statistical association was found (p>0.05) between seropositive values and the municipalities, indicating that animal was seropositive in similar proportions in the three municipalities. Female sex and older animals (>24 months) were a significant risk factor for BHV-1 and BPI-3V infection. Regarding the clinical signs, there was a statistical association (p<0.05) between the seropositive values of BVDV and most of clinical signs observed, except for abortion. CONCLUSION: This research confirms the high seroprevalence of the respiratory viral pathogens in nonvaccinated cattle within the study areas. Therefore, appropriate sanitary management practices and routine vaccination programs should be adopted to reduce the seroprevalence of these infectious agents.

Current Animal Models for Understanding the Pathology Caused by the Respiratory Syncytial Virus.

The human respiratory syncytial virus (hRSV) is the main etiologic agent of severe lower respiratory tract infections that affect young children throughout the world, associated with significant morbidity and mortality, becoming a serious public health problem globally. Up to date, no licensed vaccines are available to prevent severe hRSV-induced disease, and the generation of safe-effective vaccines has been a challenging task, requiring constant biomedical research aimed to overcome this ailment. Among the difficulties presented by the study of this pathogen, it arises the fact that there is no single animal model that resembles all aspects of the human pathology, which is due to the specificity that this pathogen has for the human host. Thus, for the study of hRSV, different animal models might be employed, depending on the goal of the study. Of all the existing models, the murine model has been the most frequent model of choice for biomedical studies worldwide and has been of great importance at contributing to the development and understanding of vaccines and therapies against hRSV. The most notable use of the murine model is that it is very useful as a first approach in the development of vaccines or therapies such as monoclonal antibodies, suggesting in this way the direction that research could have in other preclinical models that have higher maintenance costs and more complex requirements in its management. However, several additional different models for studying hRSV, such as other rodents, mustelids, ruminants, and non-human primates, have been explored, offering advantages over the murine model. In this review, we discuss the various applications of animal models to the study of hRSV-induced disease and the advantages and disadvantages of each model, highlighting the potential of each model to elucidate different features of the pathology caused by the hRSV infection.

Bovine respiratory syncytial virus seroprevalence and risk factors in non-vaccinated dairy cattle herds in Brazil.

BACKGROUND: The cattle industry is one of the most important Brazilian agribusiness sectors and is a strong contributor to the national economy. Annually about 44.6 million calves are bred, which makes the optimal management of these animals extremely important. Several diseases can affect the initial stages of the bovine production chain, being the bovine respiratory syncytial virus (BRSV) one of the most relevant pathogens. This study aimed to characterize the epidemiology of BRSV infection in dairy cattle herds of São Paulo State, Brazil, using serological and risk factors analyses. For that, 1243 blood samples were collected of animals from 26 farms and a questionnaire about possible risk factors for BRSV prevalence was performed. The obtained blood sera were analyzed using virus neutralization test (VNT). RESULTS: VNT results showed high BRSV prevalence in dairy cattle herds, reaching 79.5% of seropositivity. The BRSV seroprevalence among studied farms ranged from 40 to 100%. The analysis of risk factors indicated that the age group and the occurrence of coinfection with bovine herpesvirus 1 (BoHV-1) and bovine viral diarrhea virus 1 (BVDV-1) should be associated with a higher prevalence of BRSV, while natural suckling was considered a protective factor. CONCLUSIONS: The study showed that adult animals over 1 year old are an important risk factor for the high seroprevalence of BRSV in herds. The high BRSV prevalence associated with BoHV-1 and BVDV-1 suggests that biosecurity measures should be applied in order to reduce viral dissemination. Additionally, the natural suckling may be an important management to protect calves from high BRSV seroprevalence.

Molecular survey of infectious agents associated with bovine respiratory disease in a beef cattle feedlot in southern Brazil.

We investigated the occurrence of infectious pathogens during an outbreak of bovine respiratory disease (BRD) in a beef cattle feedlot in southern Brazil that has a high risk of developing BRD. Nasopharyngeal swabs were randomly collected from steers ( n = 23) and assessed for the presence of infectious agents of BRD by PCR and/or RT-PCR assays. These included: Histophilus somni, Mannheimia haemolytica, Pasteurella multocida, Mycoplasma bovis, bovine respiratory syncytial virus (BRSV), bovine coronavirus (BCoV), bovine viral diarrhea virus (BVDV), bovine alphaherpesvirus 1 (BoHV-1), and bovine parainfluenza virus 3 (BPIV-3). Pulmonary sections of one steer that died with clinical BRD were submitted for pathology and molecular testing. The frequencies of the pathogens identified from the nasopharyngeal swabs were: H. somni 39% (9 of 23), BRSV 35% (8 of 23), BCoV 22% (5 of 23), and M. haemolytica 13% (3 of 23). PCR or RT-PCR assays did not identify P. multocida, M. bovis, BoHV-1, BVDV, or BPIV-3 from the nasopharyngeal swabs. Single and concomitant associations of infectious agents of BRD were identified. Fibrinous bronchopneumonia was diagnosed in one steer that died; samples were positive for H. somni and M. haemolytica by PCR. H. somni, BRSV, and BCoV are important disease pathogens of BRD in feedlot cattle in Brazil, but H. somni and BCoV are probably under-reported.

Parainfluenza-3 and bovine respiratory syncytial virus: intraherd correlation adjusted for sensitivity and specificity / Parainfluenza-3 y virus respiratorio bovino sincitial: correlación intrahato ajustado por la sensibilidad y especificidad

Objective. The purpose of this study was to compare the intra-class correlation coefficients (ICC) and design effects (D) estimates adjusted or unadjusted for sensibility (Se) and specificity (Sp) of the diagnostic tests using a Bayesian procedure. Materials and methods. Sera from 232 animals from 44 randomly selected herds, to detect antibodies against parainfluenza-3 virus (PIV3) from non-vaccinated dual-purpose cattle from Colima Mexico, were used. Only 176 animals from 33 herds were used to evaluate the presence of the bovine respiratory syncytial virus (BRSV). Results. The ICC and D values adjusted and unadjusted for PIV3 were 0.33, 2.73, 0.32, and 2.71, respectively. For BRSV the values were 0.31, 2.64, 0.28 and 2.49. Conclusions. The adjusted or unadjusted ICC and D estimates were similar because of the high Se and Sp of the diagnostic tests and the relatively high prevalence of the diseases here studied.

es

Doenças respiratórias em bezerros na região sul do Rio Grande do Sul: estudo retrospectivo de 33 surtos / Respiratory diseases in calves in southern Rio Grande do Sul: study of 33 outbreaks

Foram estudados 33 surtos de pneumonia em bovinos jovens na área de influência do Laboratório Regional de Diagnóstico (LRD) da Faculdade de Veterinária da Universidade Federal de Pelotas (UFPel) entre os anos de 2000 e 2011. Foram diagnosticados 18 surtos de pneumonia (54,54%) em bovinos de raças leiteiras, Holandês ou Jersey e 13 surtos (39,39%) em gado de corte ou cruzas de gado de corte. A morbidade variou entre 0,06%-100% e a mortalidade foi de 0,06%-34,6%. A doença ocorreu igualmente em todas as estações do ano e foi mais frequente em bezerros de 1-3 meses totalizando 13 surtos. Sete surtos ocorreram em bovinos entre 4-6 meses, sete entre 7-12 meses e seis surtos ocorreram em bezerros de 1-29 dias. Pneumonia enzoótica pela infecção pelo vírus sincicial respiratório bovino (BRSV) com lesões histológicas de broncopneumonia, pneumonia intersticial e presença de células sinciciais foi mais frequente em bovinos de raças de corte com dez surtos (58,8%); seis surtos dessa enfermidade ocorreram em raças de leite (35,2%). O diagnóstico foi confirmado por imuno-histoquímica em sete casos. Os sinais clínicos da maioria dos casos de pneumonia observados caracterizaram-se por dispneia, emagrecimento, apatia, tremores, bruxismo, desidratação, respiração ruidosa, tosse, corrimento nasal seroso ou mucopurulento, decúbito e morte. As lesões macroscópicas caracterizaram-se por presença de áreas de consolidação vermelho-escuras, edema e enfisema nas regiões crânio-ventrais dos lobos pulmonares cardíaco e apical ou pneumonia intersticial com distribuição difusa, edema e enfisema. Histologicamente, as lesões pulmonares eram variáveis. Broncopneumonia necrossupurativa difusa acentuada com hiperplasia de pneumócitos tipo II e edema intersticial e alveolar foi observada em 15 casos. Os resultados deste trabalho demonstram que as pneumonias são importantes causas de perdas econômicas em bovinos jovens na região de influência do LRD. Deve ser destacado que a pneumonia enzoótica devido a infecção pelo BRSV é importante tanto em bovinos de corte como de leite independente da forma de criação.(AU)

Thirty-three outbreaks involving pneumonia in young cattle diagnosed in the area of influence of the Regional Diagnostic Laboratory (LRD) of the Veterinary School of the Federal University of Pelotas (UFPel) between 2000 and 2011 were studied. Eighteen outbreaks (54.54%) were diagnosed in dairy breeds and Jersey or Holstein and 13 outbreaks (39.39%) in beef cattle or crossbred beef cattle. Morbidity ranged from 0.06% -100% and mortality was 0.06% to 34.61%. The disease occurred in all seasons of year and was more frequent in calves aged 1-3 months (11 outbreaks). Seven outbreaks occurred in cattle between 4-6 months, seven between 6-12 months and six outbreaks occurred in calves 1-30 days. Bovine respiratory disease due to infection with bovine respiratory syncytial virus (BRSV) was more frequent in beef cattle breeds with eight outbreaks (44.44%); six outbreaks of this disease occurred in calves of dairy breeds (33.33%). The diagnosis was confirmed by immunohistochemistry in seven cases. The main clinical signs were characterized by dyspnea, weight loss, lethargy, tremors, bruxism, dehydration, rapid and noisy breathing, coughing, serous or mucopurulent nasal discharge, recumbency and death. Gross lesions were characterized by dark red areas of consolidation, edema and emphysema in cranio-ventral regions of the apical and cardiac lung lobes or diffuse interstitial pneumonia, edema and emphysema. Histologically, lung lesions were variable. Diffuse bronchopneumonia necrotizing with marked hyperplasia of type II pneumocytes and alveolar and interstitial edema was observed in 15 cases. The results of this study demonstrate that pneumonia is an important cause of economic loss in young cattle in the area of influence of the LRD and that enzootic pneumonia due to BRSV infection is important in both beef cattle and milk cattle regardless of husbandry systems.(AU)

Doenças respiratórias em bezerros na região sul do Rio Grande do Sul: estudo retrospectivo de 33 surtos / Respiratory diseases in calves in southern Rio Grande do Sul: study of 33 outbreaks

Foram estudados 33 surtos de pneumonia em bovinos jovens na área de influência do Laboratório Regional de Diagnóstico (LRD) da Faculdade de Veterinária da Universidade Federal de Pelotas (UFPel) entre os anos de 2000 e 2011. Foram diagnosticados 18 surtos de pneumonia (54,54%) em bovinos de raças leiteiras, Holandês ou Jersey e 13 surtos (39,39%) em gado de corte ou cruzas de gado de corte. A morbidade variou entre 0,06%-100% e a mortalidade foi de 0,06%-34,6%. A doença ocorreu igualmente em todas as estações do ano e foi mais frequente em bezerros de 1-3 meses totalizando 13 surtos. Sete surtos ocorreram em bovinos entre 4-6 meses, sete entre 7-12 meses e seis surtos ocorreram em bezerros de 1-29 dias. Pneumonia enzoótica pela infecção pelo vírus sincicial respiratório bovino (BRSV) com lesões histológicas de broncopneumonia, pneumonia intersticial e presença de células sinciciais foi mais frequente em bovinos de raças de corte com dez surtos (58,8%); seis surtos dessa enfermidade ocorreram em raças de leite (35,2%). O diagnóstico foi confirmado por imuno-histoquímica em sete casos. Os sinais clínicos da maioria dos casos de pneumonia observados caracterizaram-se por dispneia, emagrecimento, apatia, tremores, bruxismo, desidratação, respiração ruidosa, tosse, corrimento nasal seroso ou mucopurulento, decúbito e morte. As lesões macroscópicas caracterizaram-se por presença de áreas de consolidação vermelho-escuras, edema e enfisema nas regiões crânio-ventrais dos lobos pulmonares cardíaco e apical ou pneumonia intersticial com distribuição difusa, edema e enfisema. Histologicamente, as lesões pulmonares eram variáveis. Broncopneumonia necrossupurativa difusa acentuada com hiperplasia de pneumócitos tipo II e edema intersticial e alveolar foi observada em 15 casos. Os resultados deste trabalho demonstram que as pneumonias são importantes causas de perdas econômicas em bovinos jovens na região de influência do LRD. Deve ser destacado que a pneumonia enzoótica devido a infecção pelo BRSV é importante tanto em bovinos de corte como de leite independente da forma de criação.

Thirty-three outbreaks involving pneumonia in young cattle diagnosed in the area of influence of the Regional Diagnostic Laboratory (LRD) of the Veterinary School of the Federal University of Pelotas (UFPel) between 2000 and 2011 were studied. Eighteen outbreaks (54.54%) were diagnosed in dairy breeds and Jersey or Holstein and 13 outbreaks (39.39%) in beef cattle or crossbred beef cattle. Morbidity ranged from 0.06% -100% and mortality was 0.06% to 34.61%. The disease occurred in all seasons of year and was more frequent in calves aged 1-3 months (11 outbreaks). Seven outbreaks occurred in cattle between 4-6 months, seven between 6-12 months and six outbreaks occurred in calves 1-30 days. Bovine respiratory disease due to infection with bovine respiratory syncytial virus (BRSV) was more frequent in beef cattle breeds with eight outbreaks (44.44%); six outbreaks of this disease occurred in calves of dairy breeds (33.33%). The diagnosis was confirmed by immunohistochemistry in seven cases. The main clinical signs were characterized by dyspnea, weight loss, lethargy, tremors, bruxism, dehydration, rapid and noisy breathing, coughing, serous or mucopurulent nasal discharge, recumbency and death. Gross lesions were characterized by dark red areas of consolidation, edema and emphysema in cranio-ventral regions of the apical and cardiac lung lobes or diffuse interstitial pneumonia, edema and emphysema. Histologically, lung lesions were variable. Diffuse bronchopneumonia necrotizing with marked hyperplasia of type II pneumocytes and alveolar and interstitial edema was observed in 15 cases. The results of this study demonstrate that pneumonia is an important cause of economic loss in young cattle in the area of influence of the LRD and that enzootic pneumonia due to BRSV infection is important in both beef cattle and milk cattle regardless of husbandry systems.

Detecção molecular e análise filogenética de vírus respiratório sincicial bovino (BRSV) em swabs e tecido pulmonar de bovinos adultos / Molecular detection and phylogenetic analysis of bovine respiratory syncytial virus (BRSV) in swabs and lung tissues of adult cattle

Bovine respiratory syncytial viruses virus (BRSV) is one of the etiologic agents of pneumonia in young cattle. Few studies have been made aiming detection of the virus in samples collected from adult animals, especially those asymptomatic bovines. However, it is assumed that infections in these groups may occur mostly asymptomatic and this would be an important mechanism for maintaining of BRSV in herds. In this study, the goal was to conduct an analysis of the occurrence of asymptomatic infections by BRSV in lung samples (n=68) and nasal swabs (209) taken from adult animals collected in abattoirs from Southern and Southeastern Brazil respectively, to detect via polymerase chain reaction the occurrence of infected animals in populations of adult cattle. The samples that resulted positive (6) on RT-PCR were subsequently subjected to cutting with restriction enzymes and sequencing for genetic characterization (2 samples). All samples belongs to subgroup B of BRSV, which is reported as the one circulating in Brazil. The results obtained demonstrate that BRSV may be present in samples taken from adult animals, which is in agreement the hypothesis that infections in adults run in a sub-clinical way that may be of importance as a maintenance mechanism of the virus in bovine herds.(AU)

O vírus respiratório sincicial bovino (BRSV) é rebanhos. No presente estudo, o objetivo foi realizar uma um dos agentes etiológicos de pneumonias em bovinos jo-análise da prevalência de infecções assintomáticas pelo vens. Poucos estudos foram realizados visando à detecção BRSV em pulmões (n=68) e swabs nasais (209) coletados do agente em amostras coletadas de animais adultos, e em de bovinos adultos coletadas em frigoríficos da região Sul especial de bovinos assintomáticos. No entanto, presume-e Sudeste respectivamente, no sentido de detectar por in-se que as infecções ocorridas nestes grupos possam ocor-termédio de reação da polimerase em cadeia qual a taxa rer em sua maioria de forma assintomática e este seria de animais infectados em populações de animais adultos um mecanismo importante para manutenção do BRSV nos onde não ocorram sinais clínicos da infecção. As amostras positivas à RT-PCR (6) foram posteriormente submetidas ao corte com enzimas de restrição (REA) e sequenciamento para caracterização genética do gene F (2 das amostras). Todas as amostras se enquadram no subgrupo B de BRSV, o grupo circulante no Brasil conforme estudos anteriores. Os resultados obtidos demonstram que o BRSV pode estar presente em amostras obtidas de animais sadios, reforçando a hipótese de que infecções subclínicasfazem parte do mecanismo de manutenção do vírus nos rebanhos.(AU)

Detecção molecular e análise filogenética de vírus respiratório sincicial bovino (BRSV) em swabs e tecido pulmonar de bovinos adultos / Molecular detection and phylogenetic analysis of bovine respiratory syncytial virus (BRSV) in swabs and lung tissues of adult cattle

Bovine respiratory syncytial viruses virus (BRSV) is one of the etiologic agents of pneumonia in young cattle. Few studies have been made aiming detection of the virus in samples collected from adult animals, especially those asymptomatic bovines. However, it is assumed that infections in these groups may occur mostly asymptomatic and this would be an important mechanism for maintaining of BRSV in herds. In this study, the goal was to conduct an analysis of the occurrence of asymptomatic infections by BRSV in lung samples (n=68) and nasal swabs (209) taken from adult animals collected in abattoirs from Southern and Southeastern Brazil respectively, to detect via polymerase chain reaction the occurrence of infected animals in populations of adult cattle. The samples that resulted positive (6) on RT-PCR were subsequently subjected to cutting with restriction enzymes and sequencing for genetic characterization (2 samples). All samples belongs to subgroup B of BRSV, which is reported as the one circulating in Brazil. The results obtained demonstrate that BRSV may be present in samples taken from adult animals, which is in agreement the hypothesis that infections in adults run in a sub-clinical way that may be of importance as a maintenance mechanism of the virus in bovine herds.

O vírus respiratório sincicial bovino (BRSV) é rebanhos. No presente estudo, o objetivo foi realizar uma um dos agentes etiológicos de pneumonias em bovinos jo-análise da prevalência de infecções assintomáticas pelo vens. Poucos estudos foram realizados visando à detecção BRSV em pulmões (n=68) e swabs nasais (209) coletados do agente em amostras coletadas de animais adultos, e em de bovinos adultos coletadas em frigoríficos da região Sul especial de bovinos assintomáticos. No entanto, presume-e Sudeste respectivamente, no sentido de detectar por in-se que as infecções ocorridas nestes grupos possam ocor-termédio de reação da polimerase em cadeia qual a taxa rer em sua maioria de forma assintomática e este seria de animais infectados em populações de animais adultos um mecanismo importante para manutenção do BRSV nos onde não ocorram sinais clínicos da infecção. As amostras positivas à RT-PCR (6) foram posteriormente submetidas ao corte com enzimas de restrição (REA) e sequenciamento para caracterização genética do gene F (2 das amostras). Todas as amostras se enquadram no subgrupo B de BRSV, o grupo circulante no Brasil conforme estudos anteriores. Os resultados obtidos demonstram que o BRSV pode estar presente em amostras obtidas de animais sadios, reforçando a hipótese de que infecções subclínicasfazem parte do mecanismo de manutenção do vírus nos rebanhos.

Clonagem das glicoproteínas transmembrana G e F de um isolado brasileiro do vírus respiratório sincicial bovino em sistema procarioto / Cloning of the transmembrane glycoproteins G and F from a Brazilian isolate of bovine respiratory syncytial virus in a prokaryotic system

The aim of this work was the cloning of those transmembrane glycoproteins G and F from an isolate bovine respiratory syncytial viruses (BRSV) - a Brazilian isolate of BRSV, named BRSV-25-BR in previous studies, in a prokaryotic system to proceed the sequencing of larger genomic fragments. The nucleotide substitutions were confirmed and these clones may also be used in further studies regarding the biological effects of those proteins in vitro and in vivo.

O objetivo deste trabalho foi a clonagem das glicoproteínas transmembrana G e F de um isolado de vírus respiratório sincicial bovino (BRSV) - um isolado brasileiro denominado BRSV-25-BR- que já demonstrou possuir mutações em regiões altamente conservadas do gene da proteína G - em sistema procariótico, com o intuito de sequenciar fragmentos genômicos maiores. As substituições de nucleotídeos foram confirmadas e tais clones podem ser utilizados em futuros estudos sobre os efeitos biológicos destas proteínas tanto in vitro como in vivo.

Cloning of the transmembrane glycoproteins G and F from a Brazilian isolate of bovine respiratory syncytial virus in a prokaryotic system / Clonagem das glicoproteínas transmembrana G e F de um isolado brasileiro do vírus respiratório sincicial bovino em sistema procarioto

The aim of this work was the cloning of those transmembrane glycoproteins G and F from an isolate bovine respiratory syncytial viruses (BRSV) - a Brazilian isolate of BRSV, named BRSV-25-BR in previous studies, in a prokaryotic system to proceed the sequencing of larger genomic fragments. The nucleotide substitutions were confirmed and these clones may also be used in further studies regarding the biological effects of those proteins in vitro and in vivo.(AU)

O objetivo deste trabalho foi a clonagem das glicoproteínas transmembrana G e F de um isolado de vírus respiratório sincicial bovino (BRSV) - um isolado brasileiro denominado BRSV-25-BR- que já demonstrou possuir mutações em regiões altamente conservadas do gene da proteína G - em sistema procariótico, com o intuito de sequenciar fragmentos genômicos maiores. As substituições de nucleotídeos foram confirmadas e tais clones podem ser utilizados em futuros estudos sobre os efeitos biológicos destas proteínas tanto in vitro como in vivo.(AU)

Detecção de anticorpos contra o vírus respiratório sincicial bovino (BRSV) em rebanhos leiteiros com diferentes prevalências de herpesvirus bovino tipo 1 (BoHV-1) no estado de São Paulo, Brasil / Detection of antibodies against bovine respiratory syncytial virus (BRSV) in dairy cattle with different prevalences of bovine herpesvirus type 1 (BoHV-1) in São Paulo State, Brazil

Amostras de soro de três fazendas leiteiras do Estado de São Paulo, classificadas como de alta (1, 78,6%), média (2, 40,0%) e baixa (3, 1,6%) prevalência de herpesvirus bovino tipo 1 (BoHV-1) foram coletadas para analisar a prevalência do vírus respiratório sincicial bovino (BRSV) pelo teste de virusneutralização. As prevalências de BRSV observadas nas fazendas 1, 2 e 3 foram 45,61%, 84,42% e 54,09%, respectivamente. A fazenda 2 apresentou maior prevalência de BRSV (P 0,0001) do que fazendas 1 e 3, que foram equivalentes (P = 0,2291). Dois fatores de risco, tamanho do rebanho e condições climáticas, foram associados ao BRSV. A prevalência de BRSV na fazenda 1 foi estatisticamente inferior à prevalência de BoHV-1 (P 0 ,0001). Por outro lado, as fazendas 2 e 3 possuíram prevalências de BRSV superiores às de BoHV-1 (P 0,0001 em ambas as comparações). Podemos concluir, pelo menos para as fazendas estudadas, que o BRSV e BoHV-1 não interagiram, e que as diferenças observadas entre as prevalências de BRSV e BoHV-1 em cada rebanho não tiveram importância epidemiológica.

Serum samples from three dairy farms classified as high (1, 78.6%), medium (2, 40.0%) and low (3, 1.6%) prevalence for bovine herpesvirus type 1 (BoHV-1) from São Paulo State, were collected to analyze the prevalence to the bovine respiratory syncytial virus (BRSV) by virus neutralization test. The BRSV observed prevalences for farms 1, 2, and 3 were 45.61%, 84.42%, and 54.09%, respectively. Farm 2 showed higher prevalence to BRSV (P 0.0001) than farms 1 and 3, which were equivalent (P = 0.2291). Two risk factors, herd size and milder climate conditions, were associated to BRSV. The prevalence of BRSV in farm 1 was statistically lower than BoHV-1 prevalence (P 0.0001). On the other side, farms 2 and 3 have prevalences of BRSV higher than of BoHV-1 (P 0.0001 in both comparisons). We may conclude, at least for the studied farms, that BRSV and BoHV-1 did not interact and the differences observed between BRSV and BoHV-1 prevalences into each herd did not have epidemiological importance.

Detecção de anticorpos contra o vírus respiratório sincicial bovino (BRSV) em rebanhos leiteiros com diferentes prevalências de herpesvirus bovino tipo 1 (BoHV-1) no Estado de São Paulo, Brasil / Detection of antibodies against bovine respiratory syncytial virus (BRSV) in dairy cattle with different prevalences of bovine herpesvirus type 1 (BoHV-1) in São Paulo State, Brazil

Amostras de soro de três fazendas leiteiras do Estado de São Paulo, classificadas como de alta (1, 78,6%), média (2, 40,0%) e baixa (3, 1,6%) prevalência de herpesvirus bovino tipo 1 (BoHV-1) foram coletadas para analisar a prevalência do vírus respiratório sincicial bovino (BRSV) pelo teste de virusneutralização. As prevalências de BRSV observadas nas fazendas 1, 2 e 3 foram 45,61%, 84,42% e 54,09%, respectivamente. A fazenda 2 apresentou maior prevalência de BRSV (P 0,0001) do que fazendas 1 e 3, que foram equivalentes (P = 0,2291). Dois fatores de risco, tamanho do rebanho e condições climáticas, foram associados ao BRSV. A prevalência de BRSV na fazenda 1 foi estatisticamente inferior à prevalência de BoHV-1 (P 0 ,0001). Por outro lado, as fazendas 2 e 3 possuíram prevalências de BRSV superiores às de BoHV-1 (P 0,0001 em ambas as comparações). Podemos concluir, pelo menos para as fazendas estudadas, que o BRSV e BoHV-1 não interagiram, e que as diferenças observadas entre as prevalências de BRSV e BoHV-1 em cada rebanho não tiveram importância epidemiológica.

Serum samples from three dairy farms classified as high (1, 78.6%), medium (2, 40.0%) and low (3, 1.6%) prevalence for bovine herpesvirus type 1 (BoHV-1) from São Paulo State, were collected to analyze the prevalence to the bovine respiratory syncytial virus (BRSV) by virus neutralization test. The BRSV observed prevalences for farms 1, 2, and 3 were 45.61%, 84.42%, and 54.09%, respectively. Farm 2 showed higher prevalence to BRSV (P 0.0001) than farms 1 and 3, which were equivalent (P = 0.2291). Two risk factors, herd size and milder climate conditions, were associated to BRSV. The prevalence of BRSV in farm 1 was statistically lower than BoHV-1 prevalence (P 0.0001). On the other side, farms 2 and 3 have prevalences of BRSV higher than of BoHV-1 (P 0.0001 in both comparisons). We may conclude, at least for the studied farms, that BRSV and BoHV-1 did not interact and the differences observed between BRSV and BoHV-1 prevalences into each herd did not have epidemiological importance.